By Elaine Porterfield
SEATTLE (Reuters) - A U.S. man convicted in 2003 of being the "Green River Killer" faces a 49th murder charge, filed on Monday, stemming from the death of a woman whose skeletal remains were found near Seattle in December, 28 years after she disappeared.
Gary Ridgway will be brought from his cell at the Washington State Penitentiary in Walla Walla to a courthouse in Kent, Washington, to enter an expected guilty plea on February 18, his 62nd birthday.
A plea of guilty is supposed to be his only option under an agreement Ridgway made with prosecutors in 2003 to spare him from execution in exchange for a life prison term without the possibility of parole.
Ridgway was charged with an additional count of aggravated murder in the death of Rebecca Marrero after a skull identified as belonging to her was found in December by teenagers in a wooded ravine in the Seattle suburb of Auburn. Pieces of her vertebrae also were recovered.
Marrero was 20 years old when she was last seen alive leaving a motel near the Seattle-Tacoma Airport in December 1982. She was the mother of a 3-year-old girl.
Ridgway had confessed at one point to slaying her after his 2003 conviction on 48 other murder counts, but King County Prosecutor Dan Satterberg said on Monday there was too little evidence then to include her killing in the guilty plea deal at the time.
Ridgway was arrested in 2001 and convicted of the slayings two years later. He was dubbed the Green River killer because the bodies of several of his victims in the early 1980s were found in or near the river, which runs through south King County.
(Editing by Steve Gorman and Greg McCune)